Metal nanoparticles with sharp corners: Universal properties of plasmon resonances

TL;DR

This paper predicts universal plasmonic behaviors in metal nanoparticles with sharp corners, including a red-shifted dipolar mode and localized corner modes, enabling tailored nano-structures for enhanced optical effects.

Contribution

It introduces a theoretical prediction of how corner sharpness influences plasmon resonances, providing a basis for designing nano-structures with specific optical properties.

Findings

Dipolar mode red shifts with decreasing corner curvature

Localized plasmonic modes occur at sharp corners

Resonant frequencies depend on corner angle and curvature

Abstract

We predict the simultaneous occurrence of two fundamental phenomena for metal nanoparticles possessing sharp corners: First, the main plasmonic dipolar mode experiences strong red shift with decreasing corner curvature radius; its resonant frequency is controlled by the apex angle of the corner and the normalized (to the particle size) corner curvature. Second, the split-off plasmonic mode experiences strong localization at the corners. Altogether, this paves the way for tailoring of metal nano-structures providing wavelength-selective excitation of localized plasmons and a strong near-field enhancement of linear and nonlinear optical phenomena.